Kate Middleton continues to struggle with acute morning sickness

The Duchess of Cambridge was released from hospital over a month ago, but sources say she is still suffering from an extreme form of morning sickness called hyperemesis gravidarum.

Kate has been battling with chronic nausea and an inability to keep food down since November last year.

Insiders have recently revealed that there is now real concern Kate isn't putting on enough weight due to her condition.

Mums-to-be should put on around 4lbs during their first trimester and continue putting on around a pound a week until their due date. Fortunately, Kate is now being cared for by top medical professionals who are helping her get on the road to recovery.

Doctors are trying to get her to follow a controlled, easily digestible diet of 3,000 calories a day to build up her body and strength.

Hopefully she'll soon be back on her feet and able to enjoy the remainder of her pregnancy.